Questions tagged [proof-of-work]

This tag should be used for questions regarding how Proof of Work works and Proof of Work algorithms. Proof of Work is a scheme where a 3rd party can verify that someone performed at least a certain amount of work to produce something. This is used in Bitcoin mining.

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153 views

Are there any stochastically dependent proof of work algorithms?

In bitcoin, the probability of discovering a block on the X-th hash is the same1 as it is on the Y-th hash. As such, the probability of discovery is stochastically independent. Are there proof of ...
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81 views

Theoretical security of mining bitcoins

Is it possible to change rules of mining bitcoin division? rewrite P2P bitcoin client (or write maleware) which will be pretending that fake bitcoin client is legal, original client distribute ...
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1answer
800 views

Confirmation limit

When seeing transactions I see that the number of confirmations keeps increasing without any limit. I wanted to know if there is any time limit on including a already confirmed transaction in a block ...
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4answers
885 views

Is mining the unfair part of bitcoin in the same way banks (or rather, fractionary reserve systems) are to current monetary system?

I've been reading a lot about bitcoin lately and I'm very interested. Especially, when it comes to making a currency that is way more fair, because it avoids a centralized control of it. However, in ...
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1answer
28 views

Why does it make sense for mining pools to send empty blocks to miners in Stratum v1?

I am reading the recently released specs of Stratum v1 versus Stratum v2. One of the features is that "it is equally as efficient for pools to send full blocks for miners to begin working on as it is ...
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1answer
43 views

How to model randomness in validators selection in PoS?

I searched a lot here and on the Internet to figure how how randomness selection of validators in PoS works? I understand it is a random selection based on fraction of stake a validator has, similar ...
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2answers
89 views

What is entropy mean in this context?

"The Bitcoin nonce forms part of the block header, which is used by miners to provide entropy as part of the Proof of Work process, to try and find a hash meeting the difficulty requirement." Quote ...
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1answer
126 views

Partial Proof of Work in Pools

Technically speaking a full PoW solution is one whose hash value is below a certain threshold value say V. It is not equivalent to saying that the hash value must begin with say X number of zeros (...
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1answer
35 views

Security via Proof - of - Work

I am reading Satoshi's original paper, merely for the sake of understanding the concept. I have minimal computer science background (some), mostly just mathematics. In Section 4. Proof of Work of ...
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1answer
152 views

My coin - Proof-of-Action

I am writing a project on cryptocurrencies. As a part of this project, I thought of a new token for web services exchange. I tried to combine PoW and PoS and here is what I have. I called it Proof-of-...
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4answers
113 views

Use of proof of work in bitcoin

I am trying to understand what problem in bitcoin proof of work solves and came to this somewhat helpful quote: So, for instance, if a miner controls one percent of the computing power being used ...
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1answer
144 views

Blockchain beyond bitcoin etc. - Who is mining?

People are praising the blockchain for use in all kinds of environments where a secure transaction history is required, e.g. logistics etc. My question: Let's say someone sets up a blockchain for ...
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1answer
283 views

A theoretical low cost attack scenario in PoW currencies

The scenario was designed by user:croraf and me in discussing a question of mine yesterday. To make it more clear, I want to present it here again in a stricter design. To do it in a clear way, first ...
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113 views

How does the network know the legitimate chain in a double-spend attempt?

Apologies if this has been covered, but there's one area of the Bitcoin network that is not clear in my head, and it's intimately linked to the double-spend problem. Suppose Person A is purchasing an ...
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1answer
135 views

How is mining time validated?

New target is calculated from the T(new_block-1) - T(new_block-2016). Here T is the time miner mined the block. Miner itself sets this time for the block. Thus miner can falsify this time. I see a ...
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1answer
105 views

Are transactions verified before miner solves the block?

In the PoW mining equation... Hash = (Nonce x prev_hash x list of transactions) the miners find the nonce to add the block to the blockchain and receive the block reward. As we can see, the hash is ...
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1answer
190 views

Does 4 byte Nonce enough to proof of work?

Is it always possible to find an hash value of a block, smaller than the current difficulty, just using 4 byte (Nonce) ? How can we be sure about it ?
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1answer
159 views

Zero-BTC transaction fees, service-specific mining pools and external compensation

Bitcoin is a network that is proven to be stable, but if you want applications on top of Blockchains you have to play by the rules of the system. For notary use cases (for example), where you would ...
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1answer
467 views

Abrupt increase in difficulty of proof-of-work

I am simulating a private bitcoin network that I started with the initial difficulty set to (1/2)^16, however after about 20 blocks of mining on the network it increased to 1 and has been constant ...
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1answer
20 views

A question about Proof-of-Work(PoW)

I will describe my question using an example. Let's say the network is working on adding block #100 to the blockchain. An attacker recreates block #99 with a combination of transactions that are "...
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1answer
35 views

Timer-based consensus algorithm in blockchain

Assume that there is an algorithm that ensures: 1- That a full node chooses an honest random wait time. 2- That the same node has waited the specified amount of time before proceeding to mine a block. ...
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0answers
70 views

Proof-of-Stake: How to ensure immutability of the blockchain?

In Proof-of-Work, a miner tries to solve PoW puzzle based on the hash of previous block, such that in case of changing block B_i, all blocks after that (blocks B_i+1, B_i+2, ...) are no longer valid ...
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189 views

How to check that Genesis Block has valid proof of work using CheckProofOfWork() function?

I have been learning the ins and outs of the bitcoin source code over the past 3 months but I can say I have not fully mastered it yet. I wish to understand how the genesis block is validated using ...
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4k views

altcoin debug.log shows ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0

What I have done so far: Generated new Genesis Block Generated new MerkleRoot Updated MerkleRoot Updated Genesis block values Commented out these lines Compiled on CentOS 6 Created altcoin....
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41 views

What's a good repo to fork if you want to create a blockchain like a “Math” coin or Curecoin. (mining equations, not hashes)

I want to create my own crypto currency and I want to know what's the best github repo to fork when it comes to making a blockchain that's based off of getting the miners to do mathematical ...
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160 views

Limit of Proof of Work [duplicate]

I do not have a complete understanding of bitcoin, but I feel that the PoW concept will not do it in the long run, so I need you to explain to me if I'm wrong. First of all, all this work force is ...
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0answers
107 views

What are bitcoin miners actually solving? [duplicate]

I've read all other answer, but nobody really gives an answer. Whom for are they solving, and what entity outside BTC community has benefits from all the electric energy wasted in the process of doing ...
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1answer
633 views

Where can i find proof of work in bitcoin core source code?

does anyone knows which part of the bitcoin core source code contains the proof of work for mining, creating of block and adding to blockchain? what are the files and functions involves? https://...
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168 views

Projects built on the Tendermint platform?

The Tendermint project sounds like a very promising proof-of-stake implementation. What public projects are being built on this platform?
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2answers
614 views

Why miners solve a puzzle in proof of work

I am new to block chain, In PoW, I know a puzzle is given to the miners to solve and the miner who solve the puzzle and find the nonce first will create the block. But I don't understand why there is ...
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3answers
53 views

What is resource of mining rewards

How the coins must be paid miners for mining process is provided? One of resources may be transactions fee. Is there any other resources for proving reward of miners?
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2answers
82 views

group proof of work

Right now, every node in a Proof of Work system, solves the POW puzzle independently. Is there any concept of group proof of work, where everyone in the group needs to solve part of the puzzle.
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1answer
730 views

Steal proof-of-work answer from a miner [duplicate]

Is it possible to steal proof-of-work answer from a miner who has insecure machine? Consider a miner who has insecure machine found correct answer of proof-of-work and an adversary steals this it and ...
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5answers
171 views

Application of proof of work in bitcoin

Proof of work in spam I understand very well how proof of work is used to prevent email spam for example. Reasoning is since computing the right hash (e.g. with predefined number of zeros for example)...
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1answer
64 views

Proof of work: optimal number of transactions?

I've been struggling with this Q for a while: My initial understanding was that miners start to work on PoW for new block immediately after the previous round's block is confirmed. My Q is this: ...
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1answer
23 views

What would the effect of a very long bear market be on the Bitcoin economy?

I don't mean to be a doomsday prophet or spread FUD, but I need to know if Bitcoin (or any PoW coin) investors should be concerned about the following scenario: Assume Bitcoin goes in a very long ...
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1answer
38 views

What is stopping me from modifying the mempool of my node (may it be PoS or PoW)?

I have been trying to wrap my head around some core concepts of how a blockchain works and something has been bothering me for a while. Let's consider a case where I am running a full node of a ...
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1answer
33 views

Mining operation calculation

My goal is to understand bitcoin. I have read what happens during a transaction and have a question about it: When a transaction happen, the miners compute a value called "prof of work". This value ...
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1answer
24 views

What is meant with 'the highest PoW'?

What is meant when the nodes select the chain with the highest cumulated PoW? How is the highest highest PoW calculated? I thought the concept itself is called PoW.
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1answer
120 views

Permissioned or Permissionless blockchain? Which one is PoS more adapted for?

Since in proof-of-stake (PoS) there is no mining process, according to functionality of permissioned and permissionless blockchains, which type is PoS more adapted for? In the other words, is a PoS-...
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1answer
38 views

is the proof-of-work for safety or efficiency?

i am reading the proof-of-work (aka: pow, target threshold, difficulty, etc.); my understanding is that pow adds a requirement to validate block headers, so that both benign and malign nodes need a ...
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1answer
50 views

Ethereum's PoW difficulty

Bitcoin's block time is about 10 minutes while that of Ethereum is 15 secs. Both are using PoW at this moment, right? How come Ethereum's block time is so short compared to Bitcoin? Is hashing a lot ...
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1answer
101 views

Is the bitcoin blockchain really non-corruptible? [duplicate]

Some people say that proof of work is better than proof of stake, because it's not possible to rewrite the whole blockchain on-spot. One would need to "re-mine" everything. But I think this is not ...
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2answers
197 views

Why are blocks in a permissioned blockchain linked together?

My question: Do the blocks in a blockchain without proof-of-work (i.e. a permissioned blockchain) have to be linked together via a cryptographic hash? Longer version of my question: (Please correct ...
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1answer
51 views

What are the hashes that miners need to do to create a block? [duplicate]

I’m bit stuck in the concept of mining. What are the hashes that need to be created in each block and the chain? Let’s say that we have block A - B - C forming a chain. One source said that we need ...
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1answer
94 views

When does a node mark a transaction as confirmed or unconfirmed?

As new transactions are broadcasted, the nodes keep them in a pool of unconfirmed transactions. One node will add it to a block as soon as it finds a proof of work. At the same time many other nodes ...
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1answer
177 views

How does bitcoin implement checkpoint mechanism to finalize the blockchain history?

I read in Peercoin whitepaper that to prevent large blockchain reorganization, bitcoin also implements checkpoint mechanism which finalizes the blockchain history. Can you explain how exactly bitcoin ...
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1answer
73 views

Source of entropy for PoW hash

How does bitcoin do it to generate an (upredictable) hash in each new block with sufficient randomness so that no one can precompute it?
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33 views

When does client decide to stop/cancel proof of work algorithm?

I have been reading about bitcoin and blockchain in the last few days, but I have something I don't clearly understand. The "proof of work" may take a long time for a simple node to guess, but if we ...
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89 views

How many proof-of-work algorithm exists for crypto currencies?

How many proof-of-work algorithm exists for crypto currencies ? We know PoW in Bitcoin and Etherium are different. Is there any other algorithm used for crypto currencies ?